Forced circulation water-cooled furnace door with monolithic lining



O. L. BRAUN FORCED CIRCULATION WATER-COOLED FURNACE DOOR WITH MONOLITHICLINING May 24, 1966 2 Sheets-Sheet 1 Filed July 6, 1965 Pa -.L J-:.:r

W mm M EN mm H m N m ATTORNEYS y 24, 1966 o. L. BRAUN FORCED CIRCULATIONWATER-'CQOLED FURNACE DOOR WITH MONOLITHIC LINING Filed July 6, 1965 2Sheets-Sheet OTTWIN L. BRAUN.

ATTORNEYS United States Patent 3,252,448 FORCED CIRCULATION WATER-COOLEDFUR- NACE DOOR WITH MONOLITHIC LINING Ottwin L. Braun, Pittsburgh, Pa.,assignor to Reliance Steel Products Company, McKeesport, Pa., acorporation of Pennsylvania Filed July 6, 1965, Ser. No. 469,615 3Claims. (Cl. 122-498) The present application is a continuation-inpartof my application Serial No. 185,960, filed April 9, 1962, nowabandoned.

This invention is for a water-cooled refractory-faced furnace door whichis especially designed for use on openhearth furnaces, but which is notlimited to such use.

Water-cooled doors are commonly used in combination with water-cooleddoor frames. Consequently, when the door is closed, its periphery is incontact with watercooled metal. It is common also to constructwatercooled doors with two spaced plates, one being an inner plate whichfaces the interior of the furnace, and one being an outer plate thatfaces the exterior. The two plates have their peripheral edges turnedinwardly and welded in such manner that the inner plate is recessed andsurrounded by a hollow rim. Water is circulated in the space between thetwo plates, including the rim to cool the door. The recess so formed onthe inner face of the door is filled with refractory to protect it fromthe furnace heat. Various arrangements have heretofore been provided toprovide keys to retain the refractory panel in place, includingwater-cooled studs and ribs of various kinds. Such a construction isshown in my application Serial No. 142,371, filed October 2, 1961, nowPatent 3,156,218, granted November 10, 1964.

The present invention relates to such a door, and provides an improvedconstruction in which water-cooled keys are provided for forcedcirculation of cold water therethrough in such manner that the centralarea of the door is most effectively cooled and the cooling watercirculated in a manner-to best utilize the flow of water for cooling theentire door. This is accomplished by dividing the stream of incomingwater in such manner that one part goes first to the central area of thedoor and then flows laterally toward the sides, the circulation beingforced. The other part of the stream enters the space between the twoplates forming the door, and the first stream is discharged into thesecond in this space to create turbulence and prevent laminar flow. Thecombined stream is withdrawn through a common discharge.

The invention may be more fully understood by reference to theaccompanying drawings, wherein:

FIG. 1 is a front elevational view of the furnace door;

FIG. 2 is a top view of the door partly in section;

FIG. 3 is a vertical sectional view of the door taken along the linesIII-III of FIG. 1 looking in the direction of the arrows;

FIG. 4 is the rear view of the furnace door prior to the application ofa monolithic lining;

FIG. 5 is a fragmentary sectional view taken along the lines VV of FIG.4, but with a monolithic lining cast in situ;

FIG. 6 is a fragmentary sectional view taken along the lines VIVI ofFIG. 4;

FIG. 7 is a fragmentary sectional view takenalong the lines VII-VII ofFIG. 4; and

FIG. 8 is a view similar to FIG. 7 but showing the opposite side of thedoor and illustrating a modified construction.

Referring now to the drawings Where like reference characters designatelike or corresponding parts throughout the several views, there is shownin FIG. 1, which illustrates a preferred embodiment, a furnace door 11suit- 3,252,443 Patented May 24, 1966 sists of a rigid frame portion 16having a recess 17 within which is rammed a refractory lining 18, FIG.5. The rigid frame portion 16 is composed of the front or outer plate 13with a rearwardly or inwardly-turned peripheral flange 19 which iscontinuous around the top, bottom, and sides of the door, and a back orinner plate 21 which is spaced from the front plate. The inner plate 21has an inwardly and laterally-extending peripheral portion 22, the edgeof which is sealed to the flange 19 of the front plate 13. Accordingly,the. front plate is separated from the back plate a sufficient distanceto form a cavity or chamber 23 which extends across the face of the dooras shown in FIG. 1 and across the sides,.t0p and bottom of the door bythe spacing between the peripheral portions 22 and flange 19 of theinner and outer plates, respectively.

Fixed within the recess 17 to the inner plate 21 are horizontally-spacedribs 24 of trapezoidal cross-section, for example, flow connected tovertically aligned, centrally-disposed keys comprising the rib 25. Boththe horizontal ribs 24 and the vertical keys 25 are suitably sealed bywelding to the recessed exposed area of the inner plate 21 of the door.The horizontal ribs 24 open into side channels 26 and 27 of the door asshown best in FIGS. 4 and 7.

An inlet conduit 28 is passed through the top of the door and is coupledto a T fitting 29, which is contained wholly within the side channel 27at the top of the door 11. From the T fitting 29 ahorizontally-extending pipe 31 is posi tioned within the top channel 32of the door and opens only into the vertical keys 25. A conduit 33 isalso connected to the T fitting 29 and depends vertically within theside channel 27 of the door to open at point just above the bottomchannel 34 of the door. An outlet pipe 35 is connected through the topof the door at the side opposite the inlet conduit 28 and is in opencommunication with the side channel 26. The top channel 32, bottomchannel 34 and side channels 26 and 27 form a continuous hollow rimabout the door periphery which opens into the chamber 23.

When the door is lifted to the open position, the bottom is stillexposed to the furnace heat so that unlikeother areas of the door, it ispractically continuously exposed, for which reason it is especially, andin this regard, a maximum amount of circulation is necessary in thisarea of the door. Water is therefore forced under pressure through theinlet conduit 28 with more than fifty percent of the volume of flowcontinuing downwardly through the conduit 33 to empty into the bottomsection of the door, the balance being directed through the horizontalpipe 31 through the vertical key 25 and horizontal ribs 24 and outwardlythrough apertures or ports 36 into the side channels 26 and 27. Formaximum cooling it was discovered that 62 percent of the incoming watershould be fed to the bottom section of the door through the conduit 33.The horizontal ribs and keys embedded in the monolithic lining assist insupporting the monolithic lining particularly when the lining approachesa fiuxing temperature, while at the same time the forced circulation ofcold incoming water down the center of the door, first through thevertical keys 25 and then laterally to each side, effectively cools thecentral area of the door. Water discharged under pressure from the endsof the horizontal ribs into the space between the two plates combineswith and imparts turbulence to the body of water inthis space,disturbing laminar or quiescent flow, and aiding in avoiding anystagnant areas. Suitable cleanout openings 37 are provided through thebottom of the door.

As shown in section in FIG. 5, the refractory monolithic lining ispositioned in the recess and is anchored therein principally by means ofthe ribs 24. In some instances it has been found desirable to utilizewelding studs 38, which project from the ribs 24 and the keys 25 atregular intervals and which are also embedded in the lining material inorder to more effectively tie the lining onto the door.

The metal structural members of the door in direct surface contact withthe lining 18 such as the back plate 21,

.keys 25, and ribs 24, transfer by conduction the heat absorbed by thelining 18, which has radiated from the combustion zone of the furnace,for example, to a coolant such as water which is circulated in thechamber 23, channels 26, 27, 32 and 34, from the ribs 24 and the conduit33. The water is fed directly via the conduit 33 to the bottom area ofthe door in an amount greater than that fed through the pipe 31, keys25, and ribs 24. In this manner the circulation system indicated by flowarrows in FIG. 4 is most effective in cooling the door lining, thereuponextending the useful period of service of the door.

In the modification shown in FIG. 8 where like reference numerals areused for those parts that correspond to FIG. 7, the passages in thehorizontal keys open directly into the space 23 through ports 22a in thepanel 21 near the outer ends of the keys, instead of into the verticalchannel portions 26 and 27. more effectively imparts turbulence to thewater in the chamber 23 and more effectively diffuses the two streams ofwater before the water is carried out through the common discharge pipe28, especially near the central area of the door.

It is manifest that the above-described embodiment of the invention ismerely illustrative and that numerous modifications may be made withinthe spirit and scope of the invention.

I claim:

1. A furnace door having a top, bottom and sides and having front andrear faces comprising spaced front and rear plates defining between thema water-circulating space, the two plates having marginal flanges thatare sealed together forming a hollow rim about the rear face of the doordefining a refractory receiving recess about the rear plate, the hollowinterior of the rim forming a part of said water-circulating spacebetween the two plates, a pair of transversely-extending spaced hollowribs in the recess sealed to the rear plate forming water-circulatingducts across the rear plate, a vertical rib in the recess extendingdownwardly from said hollow rim from the top approximately midwaybetween the sides of the door and opening into saidtransversely-extending hollow rim, a water supply pipe extending downthe interior of the door at one side and terminating near the bottom forintroducing water directly into the circulating space between theplates, a branch pipe leading from said water supply pipe through thewater-circulating space at the top of the door and opening only intosaid vertical rib whereby water therefrom flows from the supply pipeinto the vertical rib at the center of the door and thence from thevertical rib it divides first into each of the transverselyextendin-gribs where the stream again divides and the flow is from the centerlaterally toward each side of the door, the ducts provided by saidtransversely-extending ribs opening through ports adjacent-their endsinto the water- This arrangement circulating space between the plates sothat the water discharged from the ducts is forced into the water insaid space to commingle with the water introduced directly into saidspace through said supply pipe, said ribs forming pockets over therecessed area of the door and watercooled keys for retaining refractorymaterial in the recessed area of the door over and around the keys, saidwater supply pipe having an external connection near the top of the doorfor connection with a source of water under pressure, and a waterdischarge pipe leading from the water-circulating space through the doorat the top at the side opposite the water supply pipe.

2. A water-cooled furnace door comprising:

(a) inner and outer spaced metal plates having inwardly-turnededge'fianges, the plates providing between them a water-circulatingspace,

(b) said inwardly-turned flange portions being welded together toprovide a hollow rim about the door that forms a continuous part of thewater-circulating space between the plates, a recess being formed aboutthe exposed face of the inner plate surrounded by said rim,

(c) a plurality of vertically-spaced hollow keys secured to said innerplate within the recess and extending horizontally thereacross from oneside to the other and forming with the inner plate horizontal ducts,

(d) a duct-forming vertical hollow key in the recess similar to thehorizontal keys extending down from the rim at the top of the door atthe center thereof and intersecting and opening into each of thehorizontal ducts,

(c) said horizontal ducts having discharge ports near the opposite endsthereof through which water may be discharged from said ducts into thewater-circulating space between the plates,

(f) a water supply pipe extending through the door at the top, said pipehaving one branch inside said space extending downwardly inside the doorand terminating in the lower portion of said space,

(g) said pipe having a second branch inside said space opening only intosaid vertical duct-forming key near the top of the door and so connectedthat the stream of water supplied thereto flows down the vertical ductand the flow is then divided into each of the horizontal ducts, wherebysuch water is coldest at the central area of the door and flowslaterally from the center of each horizontal duct in opposite directionstoward the sides, finally discharging into and effecting the flowpattern of the water entering said door through the first branch,

(h) an outlet pipe for the discharge of water in the upper part of thedoor spaced from the supply pipe, and

(i) a refractory lining in the said recess on the inner face ofthe doorconfined therein by said rim and the duct-forming keys.

3. A water-cooled furnace door as defined in claim 2 in which saidbranch pipes are so proportioned that the flow of water in the firstbranch is greater than the flow through the second branch.

References Cited by the Examiner UNITED STATES PATENTS 806,381 12/1905Weller l22497 2,766,736 10/1956 Del Buono 122-498 2,864,345 12/1958Reighart 122498 3,019,775 2/1962 Robinson 122498 0 KENNETH w. SP'RAGUE,Primary Examiner.

1. A FURNACE DOOR HAVING A TOP, BOTTOM AND SIDES AND HAVING FRONT ANDREAR FACES COMPRSING SPACED FRONT AND REAR PLATES DEFINING BETWEEN THEMA WATER-CIRCULATING SPACE, THE TWO PLATES HAVING MARGINAL FLANGES THATARE SEALED TOGETHER FORMING A HOLLOW RIM ABOUT THE REAR FACE OF THE DOORDEFINING A REFRACTORY RECEIVING RECESS ABOUT THE REAR PLATE, THE HOLLOWINTERIOR OF THE RIM FORMING A PART OF SAID WATER-CIRCULATING SPACEBETWEEN THE TWO PLATES, A PAIR OF TRAVERSELY-EXTENDING SPACED HOLLOWRIBS IN THE RECESS SEALED TO THE REAR PLATE FORMING WATER-CIRCULATINGDUCTS ACROSS THE REAR PLATE, A VERTICAL RIB IN THE RECESS EXTENDINGDOWNWARDLY FROM AID HOLLOW RIM FROM THE TOP APPROXIMATELY MIDWAY BETWEENTHE SIDES OF THE DOOR AND OPENING INTO SAID TRANSVERSELY-EXTENDINGHOLLOW RIM, A WATER SUPPLY PIPE EXTENDING DOWN THE INTERIOR OF THE DOORAT ONE SIDE AND TERMINATING NEAR THE BOTTOM FOR INTRODUCING WATERDIRECTLY INTO THE CIRCULATING SPACE BETWEEN THE PLATES, A BRANCH PIPELEADING FROM SAID WATER SUPPLY PIPE THROUGH THE WATER-CIRCULATING SPACEAT THE TOP OF THE DOOR AND OPENING ONLY INTO SAID VERTICLA RIB WHEREBYWATER THEREFROM FLOWS FROM THE SUPPLY PIPE INTO THE VERTICAL RIB AT THECENTER OF THE DOOR AND THENCE FROM THE VERTICAL RIB IT DIVIDES FIRSTINTO EACH OF THE TRANSVERSELYEXTENDING RIBS WHERE THE STREAM AGAINDIVIDES AND THE FLOW IS FROM THE CENTER LATERALLY TOWARD EACH SIDE OFTHE DOOR, THE DUCTS PROVIDED BY SAID TRANSVERSELY-EXTENDING RIBS OPENINGTHROUGH PORTS ADJACENT THEIR ENDS INTO THE WATERCIRCULATING SPACEBETWEEN THE PLATES SO TAHT THE WATER DISCHARGED FROM THE DUCTS IS FORCEDINTO THE WATER IN SAID SPACE TO COMMINGLE WITH THE WATER INTRODUCEDDIRECTLY INTO SAID SPACE THROUGH SAID SUPPLY PIPE, SAID RIBS FORMINGPOCKETS OVER THE RECESSED AREA OF THE DOOR AND WATERCOOLED KEYS FORRETAINING REFRACTORY MATERIAL IN THE RECESSED AREA OF THE DOOR OVER THEAROUND THE KEYS, SAID WATER SUPPLY PIPE HAVING AN EXTERNAL CONNECTIONNEAR THE TOP OF THE DOOR FOR CONNECTION WITH A SOURCE OF WATER UNDERPRESSURE, AND A WATER DISCHARGE PIPE LEADING FROM THE WATER-CIRCULATINGSPACE THROUGH THE DOOR AT THE TOP AT THE SIDE OPPOSITE THE WATER SUPPLYPIPE.